(II.) The analysis of a paper naturally divides itself into two parts:—(a) The determination of the nature of the fibrous material of which it is composed; and (b) the identification of such adventitious substances as size and filling material.
(
a
A fragment of the paper is soaked for some time in glycerine, and is then carefully teased out with a pair of needles, and the fragments laid on a glass slip with a drop of glycerine. A cover-glass is then laid on and lightly pressed down so as to spread the fibres in a thin layer.
The microscopical features of the different fibres have been already described, and it is only necessary now to summarise the chief characteristics of the more important materials.